A63-11
AMERICAN WOOD PROTECTION ASSOCIATION STANDARD
© 2015 All Rights Reserved
STANDARD METHOD TO DETERMINE THE VALENCY STATE OF THE
ARSENIC COMPONENT OF ARSENIC CONTAINING SOLUTIONS
Jurisdiction: AWPA Technical Committee P-5
Adopted in 2011, this standard was developed from AWPA Standard A2, Method 12.
This AWPA Standard is promulgated according to an open, consensus procedure. Using this standard in no way signifies standardization of a
chemical or wood protection system in AWPA Standard U1.
1.0 Scope:
1.1. This method is intended for testing batches of
concentrated air-oxidized ammoniacal trivalent arsenic-
containing solutions, to confirm that at least 99.5% of the
arsenic has been fully oxidized to the pentavalent state.
2.0 Summary:
2.1. The complete oxidation of trivalent to pentavalent
arsenic solutions is determined by a starch-iodine reaction.
2.2. This standard replaces AWPA Standard A2.12.
3.0 Safety Precautions: The collection, storage, handling,
and disposal of all materials should be done in accordance
with standard laboratory safety procedures. Not all general
safety concerns associated with this standard are addressed
here. It is therefore the responsibility of the user to establish
and follow appropriate good laboratory practices and general
safety precautions where applicable.
4.0 Apparatus:
4.1. Appropriate analytical balance.
5.0 Reagents:
5.1. Tartaric acid solution: Dissolve 27 g of tartaric acid in
400 ml of water:
5.2. Saturated sodium bicarbonate solution: Add 45 g of
sodium bicarbonate to 400 ml of water, and swirl
occasionally until most of the sodium bicarbonate goes into
solution. Do not use heat to dissolve the salt. This solution
can be kept in a stoppered flask.
5.3. Starch indicator solution: Make a paste of about 1.0 g of
soluble starch in 5 ml of water. Pour the paste into 200 ml of
water, near the boiling point, and then boil for one minute.
When the solution has cooled, add a few drops of
chloroform as a preservative and keep in a stoppered bottle.
Some batches of starch will not dissolve properly. If the
solution separates into two layers, use the clear, top layer. If
the whole solution is cloudy, prepare a fresh solution, or
obtain a different supply of starch.
5.4. Iodine solution: Add 6.3-6.4 g of resublimed iodine to a
500 ml standard flask. Add 10-12 g of potassium iodide and
not more than about 20 ml of water. Swirl the contents of the
flask at room temperature until all the iodine has dissolved,
and dilute to the graduation mark. This solution can be kept
for a few weeks if stored in a tightly-sealed, glass-stoppered,
dark bottle in a cool place.
6.0 General Method Procedures:
6.1. The sample should be taken in such a manner as to
ensure it uniformly represents a sub-part of the entire
material to be tested.
6.2. Take a sample of the ammoniacal copper zinc arsenate
(ACZA) concentrate and place in a stoppered container
(contact of the sample with air should be kept to a minimum
or else misleading results could be obtained.) Allow the
sample to settle for at least 5 min before analysis.
6.3. Add 20 ml of the tartaric acid solution to a 250 ml
Erlenmeyer flask.
6.4. Pipet exactly 2.00 ml of the ACZA concentrate into the
tartaric acid solution. The color of the solution should now
be light blue-green. If a reddish, grey, cloudy suspension is
obtained, it means that aeration of the concentrate is
required.
6.5. To the light blue-green solution, add 20 ml of saturated
sodium bicarbonate solution. The solution will now be light
blue. Add 2 ml of the starch indicator solution (§5.3).
6.6. Add one drop of the iodine solution (§5.4). This should
be done from a buret so that the drop will be about 0.05 ml.
Swirl the solution in the flask. If it immediately becomes
dark blue (similar to the color of an ACZA treating
solution), and remains dark for at least one minute, it means
that aeration of the concentrate was complete, and that at
least 99.5% of the arsenic is in the pentavalent form. If this
result is not obtained, aeration should be continued and
another sample tested later.
7.0 Calculations:
7.1 Not applicable.
8.0 Report: Report on the presence, or absence, of the
arsenic being 99.5% or more oxidized to the pentavalent
state.
9.0 Precision Statement:
9.1 No precision statement based on ASTM E-691 has yet
been developed for this Standard.
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A64-11
AMERICAN WOOD PROTECTION ASSOCIATION STANDARD
© 2015 All Rights Reserved
STANDARD METHOD TO DETERMINE THE AMOUNT OF BORON
TRIOXIDE IN SODIUM BORATE WOOD PRESERVATIVES
Jurisdiction: AWPA Technical Committee P-5
Adopted in 2011, this standard was developed from AWPA Standard A2, Method 15.
This AWPA Standard is promulgated according to an open, consensus procedure. Using this standard in no way signifies standardization of a
chemical or wood protection system in AWPA Standard U1.
1.0 Scope:
1.1 This test method is employed to determine the amount of
boron trioxide or sodium octaborate tetrahydrate in sodium
borate wood preservative solutions.
2.0 Summary:
2.1. The amount of boron trioxide in borate wood
preservative solution or solid borate preservative is
determined by titration and reported as boron trioxide or
disodium octaborate tetrahydrate (DOT).
2.2. This method replaces AWPA Standard A2.15.
3.0 Safety Precautions:
3.1 The collection, storage, handling, and disposal of
materials should be done in accordance with standard
laboratory safety procedures. Not all general safety
concerns associated with this Standard are addressed here. It
is therefore the responsibility of the user to establish and
follow appropriate good laboratory practices and general
safety precautions where applicable.
4.0 Apparatus:
4.1. Suitable analytical balance.
4.2. Titration glassware.
5.0 Reagents:
5.1. Mannitol powder - U.S.P. grade
5.2. Hydrochloric acid, about 0.5 N - Standardization not
needed
5.3. Sodium hydroxide, about 0.5 N - Purchase standardized
material or standardize using reagent grade boric acid
and precisely determine normality, refer to as Nbase
5.4. Phenolphthalein indicator - 1% solution in ethanol
(methanol or propanol may be used in place of ethanol)
5.5. Methyl red, indicator (sodium salt) - 0.1% solution in
ethanol (methanol or propanol may be used in place of
ethanol)
5.6. Distilled or deionized water
6.0 General Method Procedures:
6.1. The sample should be stirred or mixed than then taken
in such a manner as to ensure it uniformly represents a sub-
part of the entire material to be tested.
6.2. Dissolve about 1.0 g of solid preservative in about 100
ml of water, record the exact mass of solid used. Refer to
this as g of sample. Gentle heating may be necessary, but
cool to room temperature before titrating.
6.3. Add 3 drops of methyl red indicator and stir. Add HCl
solution until solution turns pink then add about 1 ml of
excess acid.
6.4. Gently boil this solution for 3 minutes to remove CO2
and cool in an ice bath to room temperature.
6.5. Titrate the solution with standardized NaOH to a peach-
yellow color (the methyl red neutral point). Up to this point,
the volumes of acid and base do not have to be recorded.
6.6. To the solution now add 6 drops of methyl red indicator,
8 drops of phenolphthalein, and excess mannitol powder
(approximately 30-35 g), and stir to dissolve. The solution
will turn a red/pink color.
6.7. Titrate the solution with standardized NaOH. The color
will change from red/pink to yellow and back to red/pink,
which is the end point. Care should be taken to titrate slowly
so as not to miss seeing the yellow color entirely.
6.8. To be sure that the titration is complete, add
approximately 10 g of mannitol powder to the solution and
stir to dissolve. If the solution changes back to a yellow
color, then continue to titrate. If there is no color change
upon mannitol addition, then the titration was complete after
step 6. Record the volume of NaOH added in step 6 and 7, in
ml, as Vbase.
6.9. Alternatively, to analyze the treating solution, accurately
weigh out (to 0.01 g) 5 to 7 g of treating solution into a 250
ml Erlenmeyer flask. Refer to this as grams of sample. Add
distilled water to bring the total volume to approximately
100 ml; swirl to mix and then analyze as before starting with
Step 6.3.
7.0 Calculations:
% B2O3
3.481 x (Vbase) x (Nbase)
grams of sample
% B 2O 3 x 0.3106 = % Boron (B)
% B
0.21
%D.O.T . ; Where DOT is disodium octaborate
tetrahydrate
8.0 Report:
8.1 Report the percent boron as B 2O 3 and/or DOT.
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A64-11
STANDARD METHOD TO DETERMINE THE AMOUNT OF BORON
TRIOXIDE IN SODIUM BORATE WOOD PRESERVATIVES
Page 2 of 2
© 2015
9.0 Precision Statement:
9.1. The following statements and table should be used to
judge the acceptability of an analysis using this method. The
precision data were developed following the guidelines in
ASTM Method E 691.
Precision Table for Determination of Boron Trioxide
Element
Boron
Boron
Boron
Expressed as
Oxide
B 2O3
B 2O3
B 2O3
Concentration
Level (wt %)
0.00 - 0.671
0.672 - 3.36
3.37 - 6.71
Confidence Limits
Repeatability
(r)
0.030
0.034
0.045
Reproducibility
(R)
0.030
0.040
0.166
The above precision statements are based on round robin data by five laboratories, each running three replicate
determinations on each of three samples covering